We are requesting from the NIH to be one of the principal sponsors of the Fourth International Conference on Systems Biology to be held at Washington University in November, 2003. A group of world-class scientists has been assembled to discuss heoretical/computational and experimental approaches for analyzing biological systems at multiple hierarchical levels. The area of systems biology is particularly relevant to modern biomedical research. Sponsorship of the Fourth ICSB would highlight NIH's longstanding commitment to supporting emerging, high impact areas of interdisciplinary bioscience, and the education of students (and institutions) who wish to contribute to these areas.